Yes... inspite of they are written and pronounced the same way, their meaning is made clear on the context. As it would not be correct to say "Ela admira ele", but then you have to change "ele" into indirect object, which is "o" for the masculine/singular and "a" for the feminine/singular.

here they are: "ME", which corresponds to "ME" in English,

"TE", which corresponds to an informal "YOU" in English,

"O", which corresponds to "HIM" or "IT" when an object is masculine.

"A", which corresponds to "HER" or "IT" when an object is feminine.

"NOS", which corresponds to "US".

"VOS" / "VOCÊS, which corresponds to plural "YOU" (as YOU GUYS),

"OS", which corresponds to a masculine "THEM", be it people or objects.

"AS", which also corresponds to a feminine "THEM" in English, be it people or objects.

For further and full information, access: http://en.wikipedia.org/wiki/Portuguese_personal_pronouns